Color artwork, which often includes a plurality of graphic or text objects, may be reproduced using any of a variety of different printing processes, including offset lithography, gravure, silk screening, or flexography. For an accurate reproduction of color variations using these methods, two or more different inks are applied, for example, to separate lithographic plates. Generally, three different ink colors (and hence three different lithographic plates) are needed to approximately reproduce the spectrum of colors seen with a human eye. However, in some cases, for example, where only gray tones are needed, only two inks are used; in others, for example, where an especially bright or dark color is desired, more than three inks may be used.
Conventionally, a specific mixture of colors, called “process colors”, have been used in commercial printing processes. Process colors are mixed from four “pure” process colors, which include cyan, magenta, yellow, and black, or “CMYK”. (The “K” refers to black; “B” is not used in order to avoid confusion with blue). Many commercial printing processes use CMYK color inks, either pure or in mixture, to reproduce in print color objects within a piece of artwork. However, in cases where an especially bright or dark shade of color is desired, a separate “spot” color, which requires its own specially mixed ink, may also be used.
Conventional color mixing techniques have several disadvantages, especially for large scale reproduction of color artwork using commercial printing processes. Artists do not usually specify what mixture of CMYK ink should be used to produce a color desired for a particular object in a piece of artwork. Rather, a commercial printer or prepress operator must try to match specified colors as closely as possible, sometimes by trial and error. Unfortunately, some colors specified by artists (for example, metallic or fluorescent colors) are not reproducible using CMYK inks. Where many such colors are present in a piece of artwork, it is infeasible for a plurality of separate non-CMYK inks to be mixed for each color.
Using digital computers, color mixing has been simplified. With a digital computer running dedicated prepress processing software, a user of the software (e.g., a prepress operator) may specify what particular blend of CMYK pure process color inks should be used to “fill” objects within a piece of digital artwork. When colors are specified digitally, errors are minimized during print processing since printers spend less time determining what mixture of inks was intended. But the use of conventional prepress software does not eliminate the need for an artist or prepress operator to assign to each object within a piece of digital artwork a specific digital mixture of colors. Conventional prepress processing software include the Esko-Graphics Barco™ or Artwork Systems Artpro™ packages. Currently, commercial software packages for prepress processing have several distinct disadvantages.
Some disadvantages to the use of such commercial software packages for prepress processing include the need for file format conversions. The file format of artwork submitted for prepress work is usually different from the file format used by prepress software packages. Finished designs are usually produced in an artwork production environment, such as Adobe lllustrator™ or Macromedia Freehand™, and must be converted from the file format used by the artwork production software into the file format for the prepress software package before prepress processing can be completed. File conversion errors occasionally result.
Other disadvantages of file conversion include an inability of artists to make even minor changes to artwork already submitted for prepress processing. Thus, artwork usually goes through a long approval process before being submitted for prepress processing. Changes after submission may be costly or impossible. A minor change to a small aspect of artwork submitted for prepress processing may require a large amount of additional work to correct. For example, if a company wishes to make a slight alteration to a text object, the prepress processing might have to revert back to the original file (supplied), edit the text, export the text out into a suitable format, import the file into a proprietary format and re-position the amended text.
Attempts have been made to improve the accuracy and efficiency of color management by transferring digital artwork from the native artwork production environment to a server used for digital prepress processing. In systems of this kind, a piece of digital artwork (such as an Adobe Illustrator™ file) is transferred to a server, which does prepress processing to text and graphic objects within the file before transferring the file back to the native artwork production environment. Disadvantageously, the use of a server and network increases the cost of prepress processing (for example, because network bandwidth must be expanded to accommodate transfer of large graphics files back and forth from the server). Also, the use of such servers often requires file conversions, resulting in the same disadvantages described above.
An additional disadvantage to the use of proprietary file formats and software packages is that prepress software packages require extensive training. Hence, additional company resources (beyond those necessary for simply creating artwork) are required for artwork to be prepared for printing. A smaller company might be unable to afford high quality artwork for advertisements or product packaging simply because prepress processing is unaffordable.
There is, therefore, a need for an efficient prepress tool for applying accurate, high quality color mixtures to digital artwork within a native artwork production environment.